Compositions comprising polyester plasticizers



J. L. LUDLOW June 5, 1956 COMPOSITIONS COMPRISING POLYESTER PLASTICIZERS Filed March 30. 1951 EXUDATION OF M D GLYCOL- ADIPATE PLASTIC RS FROM POLYVIN HLORIDE C P0- SITIONS AND 100% TETRAMETHYLENE GLYGOL AAAAAAAAA AAAAAAM V\/\/V\ AMAA mm M \AM M INVENTOR.

JOHN L. LUDLOW A TTORNEY.

United States Patent COMPOSITIONS COMPRISING POLYESTER PLASTICIZERS John L. Ludlow, Wilmington, Del, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware 7 Application March 30, 1951, Serial No. 218,471

' 1 Claim. (Cl. 260-75) This invention relates to mixed polyester plasticizers and compositions-containing the same. Thisapplication is a continuation-in-part of my copen'di'ng application S. N. 166,303 which was filed on June 6, 1950.

Heretofore certain polyesters, including alkyd resins, have been employed as plasticizers for vinyl chloride polymers. -Moreover, numerous high-boiling monomeric esters also have been employed as plasticizers for polyvinyl chloride; included among these are branched chain dialkyl phthalates, tricresyl phosphate, phthallylglycollyl' esters, and many others.

The present invention is directed to the preparation of plasticizers from certain products obtained by oxidation of cyclohexane and/ or related compounds.

none, a mixture of succinic acid, glutaric acid and other products is obtained, after separation of adipic acid, and this mixture has recently been utilized for the first time,

by hydrogenation to polyhydroxy compounds as dlSr.

closed in the copending application of G. F. Curtin, Jr.,

S. N. 146,155, filed February 24, 1950. The said polyhydroxy compounds are hexamethylene glycol, pentamethylene glycol, and tetramethylene glycol. While these individual glycols give useful plasticizers when esterified do not exude rapidlyfrom blends thereof with polyvinyl 2 tion do not exude from a polyvinyl chloride composition over an extended period of time and they are therefore superior to the polyesters prepared from single glycol com ponents, which exude relatively rapidly. For exaniple', the polyester made from approximately equivalent quantif ties of pentamethylene glycol and hexamethylerie glycol with a few percent of tetramethylene glycol did not exude in 20 months while the polyesters from adipic acid and pentamethylene glycol individually exuded in less than one month;

In the compositions of this invention the acid component of the ester is adipic acid. Other diabasic acids formed in the oxidation of cyclohexane, cyclohexanone' and/or cyclohexanol may also be included. Moreover, the terminal hydroxyl of the polyester may be esterified with acetate or other alkanoate radical if desired. Moreover, esterification of the terminal acid groups or" the polyester plasticizers with methanol has a highly beneficial effect.

The polyester plasticizers of this invention are compatible with the following resins: polyvinyl chloride, polyvinyl chloride-acetate, nitrocellulose, cellulose acetate-butyrate and polyvinyl butyral, among others.

In the preparation of adipic acid by oxidation of such compounds as cyclohexane, cyclohexanol and/or cyclohexa chloride. ,Anotherobject' is to provide improvednplas 1 ticized polyvinyl chloride compositions. of the invention appear hereinafter.

It has been discovered in accordance with this invention Other objects that an improved plasticizer composition comprises a polyester of adipic acid-with glyeols," said polyester having combined therein the relative weights of hexamethyl- 'ene glycol, pentamethylene glycol, and tetramethylene glycol indicated by the area within the broken lines in the trilinear diagram appended hereto. The improved tion head for removing the distillate.

heated, with a Glascol heating mantle, for four hours results herein disclosed are obtained when thesepoly-Q esters have an acid number not exceeding 21, and are sufficiently highly polymerized to have an inherent viscosity, measured on-an acetone solution of 1% concenn t (solvent) inherent J VlSCOSitY where 1 (solution) and t (solvent) are the efllux times of the. solution and solvent through a capillary viscometer. The concentration is expressed in grams of polyester/ milliliters of solution. A, i g w The mixed glycol adipic acid polyesters of this inven- 62 parts of polyvinyl chloride 38 parts of plasticizer, and I 2.5 parts of basic lead carbonate were dry-mixed with a spatula. The mixture was then milled on a rubber mill at a temperature of C. for fifteen minutes after the composition had sheeted. Moldings (3" x 5" x 0.070" size were prepared by heating at C. for 6 minutes with no pressure and then holding for 9 minutes at a pressure at 200 p. s. i. and cooling under pressure. Samples being testedfor exudation .were stored either in envelopes or in the open. Exudation was evidenced by a greasy or oily appearance on the surface of the molding.

Example I.Comparis0n of polyhexamethylene adipate with polyester from adipic acid, hexamet hylene glycol, pen'tnmethylene glycol and tetramethyle ne glycol seventy-three and one-tenth grams of adipic acid was I placed'in a 3 neck, 500 ml.-fiask and 64.9 grams of hexamethylene glycol (10% excess) was added.- The flask was fitted with a thermometer well, an inlet for introducing nitrogen below the level of the liquid and a distilla- The mixture was and five minutes at atmospheric pressure. The maximum temperature reached was 236 C. The pressure was reduced and held at.311 mm. and the heating continued for an additional six hours and forty-five minutes during which time the maximum temperature was 269 C. The product weighed 110.9 grams and on cooling was a cream-colored, Waxy solid which had an acid number of 2.0, a hydroxyl number of 177-0, a Softening point of 57 C. and an inherent viscosity of 0.122.

A polyvinyl chloride composition containing 33 parts of this plasticizer, 2.5 parts of basic lead carbonate and 67 parts of polyvinyl chloride had the following properties:

V 1:007 Tensile Elonga- Brittleness Stiffness Days to Temperature p. s. i. q g g g g 3 25 Exude 30 0. n! 1,855 I 2, 000 2, 925 l 248 30 Days to Exu lc Time to Exude ays) Elongation, percent;

Tensile Strength,

p. s. l.

mmwmmmmmmmmmmmm ZZOMOMZZLOMZZZZZ Z l m mwmammmammfimam T Tensile Strength, p. s. i.

100% Modulus, p. s. 1.

Example II Stiffness, p. s. i.

roducts (after separation of adipic acid) obtained by st at 84 C. It is a mixture of about A polyvinyl chloride composition containing 33 parts of this placticizer, 2.5 parts of basic lead acetate and 67 parts of polyvinyl chloride had the following physical properties:

Evaluation tests were carried out on a series of poly- Brittleness Temperature ing table.

The flask was fitted with a ther- TABLE L-PHYSICAL PROPERTIES OF POLYVINYL CHLORIDE COMPOSITIONS PLASTICIZED WITH 38% OF MIXED GLYG OL-ADIPIC ACID POLYESTERS For comparison with the above result, 400 grams of 264 C. The mixture was heated under a vacuum of 15 esters of adipic acid, with results as set forth in the follow- S gs a m mn m m C 8 e m Z M b O I m m m H o o Wk n o M a m 2;. s e A m. m eHm a m t m n 1 a a 0 1 E t u r G T a o a e N n flh m m m m m 0 or n 1 86 70 3 0 2f 5 0 m mm mwmmmwmmmawmmmm w m 5 H t mm m m wmmmmamwmmmmmwm r n v. r C e r n m. P M H S P P m m u H b m m m m m o l i v. a I 5 5 0 ma mwmwmmwmmmmmmmm m a s m m a m mm mmwmmwmmmww 1m LLLLLLLLLLLLLLI, m m m P 0 l E m 11L 1 1 1 1 1 1 1 1 1 .1 r r i f w on M M Ma m o e m mm r V. S 50903 0 8 5. wflh .8mm 6 .0 5 u 50 5 mmade a ammmm 5 w P M. me a? aenai So. 1 ww nuw 1 1 1 1 1 1 1 ea w a s O s a u Hmm m n m mw e a 5 .e .a c uuS 86%6m0%5%1662%1 m a 0 L W C 22 3 2 2 3122 2 l mmmo M m m h m mwwo mmwmummmwmuwmmu Br mw wm m .mn aw m d A L n mm mm OE 1 wmmm F n wfi m PL n F P Me u mm 0 on .e moewamumm "a m o u 5 r M0 Lmd m EE M .wW. 08145 6 2 7 1n0H.w.w 8 m r t .1 11 IL s .mmn mnmamnmmmn mmm mwwwwm m an m 1 aaanmaemmmnuan w us moooooooodououo ma h E- Y M mu ual .1 .JJJJJ O .1 V ceg m PD 1 00000000000000 P .mv w m s n o m m. v mw i o P a 0. a 3 m mm o r. N W77874176053410 wmm w L 0 N W7936245636032 m @LaLLLaLLaLLLLa mmm W m weoaooLaLaLzaLa C D. n H C A mm mmmm ME A mmwmm "mm meow mmm m mammwma "mmmmm. 1 C 1 a e H d C 1 m .mhmu fi 6 PW i mu wm m .a 4 m a ZUOOOSS 0 50 H )1 e l.- .500 55 mm C ml234 m7mwm33m B H m C m lnowmvigm m .2. mw f E m am 1. 55m0m nlom O L e P 0 IIIII l om e B P m "III: .nq g A ael n T a r g .n M e m .a 5 3 d r e b adipic acid was placed in a three liter, three neck flask and 431 grams of mixed glycols (a mixture of equimolal amounts of hexamethylene glycol and pentamethylene glycol with a small amount (ca. 5%) of tetramethylene 5 glycol, hydroxyl number of 917) was added. This is a 29% excess of glycols.

rnoineter well, a high speed stirrer and a l x 30" packed column with a distillation head. Nitrogen for blanketing the reaction mixture was introduced around the stirrer 10 24 shaft. The flask was heated with a Glascol heating mantle. The mixture was heated for 11 hours and the water of reaction was withdrawn at a l/ 1 reflux ratio while the temperature rose from 128 to a maximum of mm. for 4.5 hours at a maximum temperature of 262 C.

Seven hundred two and five tenths grams of product was Obtained which 'on cooling was a slightly tannish colored solid which had an acid number of 1.4, a hydroxyl numviscosity of 0.131.

1 Composition: 62 parts PVO-Geon"-101; 38 parts plasticlzer; 2.5 parts basic lead carbonate.

Example Ill Plasticizer evaluation tests were carried out on a series of mixed glycol-mixed acid polyesters, said acids having the formula (CHa)n(COOH)2, n being 2 to 4. The results are set forth in the following table.

catalyst, methanol being taken overhead. The initial moi ratio of glycol/ester was 1.05. The heating was continued for 3.2 hours, after which acetic anhydride of the weight of polyester) was added, and the mixture was heated for one hour under reflux, after which the TABLE III.-PHYSICAL PROPERTIES OF POLYVINYL CHLORIDE COMPOSITIONS 1 PLASTICIZED WITH 38% OF MIXED GLYOOL-MIXED ACID POLYESTERS Percent Acid Polyester Composition G1 col Brittle- Time G O C y Acid I 1 M. P. ness Stifi. 100% Percent $53 3 to 4 5 a No. 0.) Temp. (p. s. i Modulus Elong. S Exude 0.1 (Days) 18 49 33 AS 0. 9 0. 108 -23 1, 135 1, 300 370 2, 525 540 7 21 72 AS 0. 7 0. 086 16. 5 -28 1, 085 1, 300 280 2, 400 270 75 AS 0. 1 0. 104 -26 1, 055 1, 500 266 2, 475 270 50 AS 0. 3 0. 100 -28 1, 255 1, 400 320 2, 550 540 1 Composition: 62 parts PVO-Geon"-101; 38 parts plasticizer; 2.5 parts basic lead carbonate.

Example IV A series of tests was made with AS-adipate polyestermodified polyvinyl chloride, with results as follows:

volatile constituents were removed at 225 C. by lowering the pressure to 10 mm.

The resulting product had an acid number of 0.8, an hydroxyl number of 0.3, and an inherent viscosity of TABLE IV.-PROPERTIES OF VARIOUS MIXED GLYCOL ADIPATE POLYESTER PLASTICIZERS IN POLYVINYL CHLORIDE COMPOSITIONS Migration Resistance Inher- Viscos- 11+ W W in iii??? r $223, 222i; 0%. Percent 55.21, No. N c. Viscosloises met 0. C. a 0 #fln, Elong. Mar, my O.+ Percent 25 O.+50% R. H. 100% Surface R. H. Marred .81 102 88 33 -5 -25 1, 940 1, 000 265 2, 870 lNone in 18 mos. 152

38 -15 7 -27 1, 140 1,360 320 2, 600 I to 2 yrs. 115 15. 1. 04 41 .087 48 3g -22 (1)33 32% g, 375 None in 16 1110s.... 132 ca. 20.

as -31 1,100 1, 400 35s 2, 900 15 1. 4 223 .033 8 38 -26 -10 -42 2, 405 1, 700 274 2, 405 1 day 1 9 177 041 8 38 -24 -10 -38 1, 865 l, 265 294 2, 125 4 days 21 21 113 136 38 -14 1., 195 1, 375 346 2, 475 None in 18 44. 5 0 .093 63 38 -10 2, 615 1, 875 206 2, 475 Yes, 18 mos.

0. 5 5 2. 4 .032 8 38 -24 -15 -32 850 900 284 2, 800 None in 11 mos 0. 14 5 2. 6 .031 8 38 21 -14 30 815 700 318 1,850 do 1 Compositions contained 33 parts plasticizer, 62 parts Geon"10l, and 4% basic lead carbonate based on the resin. ASTM tests used.

2 Inherent viscosity at 25 measured using 1% solution in acetone.

3 Clash-Berg test for torsional stiffness: at T: stifiness=45,000 p. s. 1.; T104 stifiness=l0,000 p. s. i. 4 Furniture mar-samples 2 x 2" held in contact with panel coated with nitrocellulose lacquer under M t/in. for 10 days at 25 C.

5 End groups esterified with acetic anhydride.

Example V Methyl esters of mixed acids of the formula HOOC(CH2)1LCOOH (per cent C4 acid=27.5, per cent C5=46.2, per cent Cs=26.3) were heated in a still with mixed glycols of the formula HO(CH2)11.OH (per cent 01:21.1, per cent 05:50.5, per cent 05:28.4) in the presence of 0.3% by weight of zinc borate catalyst, methanol being taken overhead. The mol ratio of glycol/ester was initially 0.8. Heating was continued at 200 to 225 C. for 2.3 hours at atmospheric pressure, at which time the ester interchange reaction was virtually complete. The pressure on the system was then lowered to 10 mm., and distillation of monomeric ingredients was completed, after which the distillation residue was cooled. The catalyst remained dispersed in the resulting polyester, which had an acid number of 0.2, an hydroxyl number of 0.1 and an inherent viscosity of 0.05. When 38% by weight of this plasticizer was milled into polyvinyl chloride (Geon101) along with 4% of basic lead carbonate as a stabilizer a product was obtained which had the properties given in Table V, Specimen A. In another preparation of polyester the methyl esters of mixed acids of the formula HOOC(CH2)nCOOH (per cent C4=25, per cent C5=50, per cent Cs=25) were heated in a still with mixed glycols of the formula HO(CH2)7LOH (per cent C4 26, per cent Cs=40.8, Cs=33) in the presence of 0.3% by weight of zinc borate 0.046. When 38% by weight of this plasticizer was milled into polyvinyl chloride (Gconl01) along with 4% of basic lead carbonate as a stabilizer, a product was obtained which had the properties given in Table V, Specimen B. Specimen C was prepared in a similar manner, but without end group acetylation, using mixed methyl esters of the same alkandioic acids (C4 acid=25%, C5=50%, Cs=25%) and the glycols (C4=25%, C5=50%, Cc=25% in the ratio of 1:0.8. Specimen C had an acid number of 0.5, hydroxyl number 10.9, and inherent viscosity 0.05. The table shows that good results were obtained even at low inherent viscosities when both the acid number and hydroxyl number were kept at a minimum.

The data when compared with the data presented hereinabove show that relatively low viscosity polyester may be used if the starting material is esterified, whereby the hydroxyl number is kept low. When no (or relatively little) of the C4 acid component is employed in the low viscosity range (down to 0.03) the hydroxyl number may be as high as about 50, without excessive exudation under humid conditions; however, when a substantial quantity of the C4 acid component is employed the hydroxyl number at these low viscosities should be kept at a minimum. Moreover, when the inherent viscosity is the 0.087 level hereinabove illustrated, it is essential that the hydroxyl number be kept below about 15 to avoid an excessive 7 exudation rate at high humidities. The table illustrates compositions in this low viscosity range, and even containing a substantial amount of Ctacid component, which nevertheless do not exhibit excessive exudation.

8 Iclairn: A plasticizer composition comprising a polyester of adipic acid, said polyester having combined therein the relative weight quantities ofthexamethylene glycol, pcnta- TABLE V.PROPERTIES OF PLASTICIZED POLYVINYL CHLORIDE CONTAINING LO\V VISCOSITY POLYESTER HAVING LO'W ACID AND HYDROXYL VALUES Percent Brittle- Exudation Designation of Stiffness gq gfi Ultimate ness specimen (p s i) t sgi) i 24 o 587 R H 50C 100 R n ion 1, 230 1, 550 277 2, 525 22 None, 1 week None, 1 week.

950 1,200 350 2, 500 -22 None, 4.5 months, Slight, 45 days. 1,360 1, 425 300 2, 550 -24 None, 3.5 months. Slight, days.

The drawing illustrates the plasticized polyvinyl chloride compositions which did not exude in several months time. The area bounded by the broken line defines the optimum compositions obtained in accordance with this invention. Typical actual exudation times are noted at various locations in the diagram.

It is to be understood that the examples given above are illustrative only and that numerous methods of practicing the invention will occur to those who are skilled in the art. For instance, the percentage of plasticizer in the polyvinyl chloride composition may be varied over a wide range, the quantity of plasticizer usually employed being, however, within the range of 25% to 75% of the total weight of plasticized resin. Antioxidants, stabilizers, etc., may be added if desired.

The plasticized polyvinyl chloride of this invention may be used in the manufacture of belts, tubing, electrical insulation (for Wire coverings, jacketing, base plugs, etc.), sheeting, moldings, paper coatings, floor tile, coated fabrics, upholstery material, seat covers, drapery material, garment bags, table covers, luggage, leather substitutes (shoe uppers, weltings) and numerous other articles of commerce, particularly those involving application at elevated temperatures and requiring resistance to migration or extraction of the plasticizer.

methylene glycol, and tetramethylene glycol defined by the area within the broken lines in the accompanying trilinear diagram, said polyester having an acid number not exceeding 21 and an inherent viscosity, measured on an acetone solution of 1% concentration of from 0.030 to 0.13], the hydroxyl number being not greater than 15 when the inherent viscosity is below 0.087.

References Cited in the file of. this patent UNITED STATES PATENTS 

